Chicago post-rock collective Isotope 217 will release their third album, Who Stole the I Walkman?, Aug. 8 on Thrill Jockey. The band, which includes Tortoise members Jeff Parker, John Herndon and Dan Bitney, blends elements of live improvisational jazz with studio manipulation and electronic rhythms and textures. Unstabl Molecule, the group's 1997 debut, was essentially a live experimental-jazz recording, while last year's Utonian Automatic EP moved closer to the mix of styles realized on Who Stole the I Walkman?. Last year, the band also put out Commander Mindfuck, a two-song collection of remixes.